To sum up and to clarify what I think is accomplished by all the foregoing reflections on Cephalus in Plato's Republic, let me cite and respond to a few prominent interpreters.
I will begin with Allan Bloom's reading, since among those I have studied it is the most different from my own . He identifies Cephalus as a representative of "ancestral piety" (Bloom, 312) which makes a claim to authority as "a practical substitute for wisdom." Socrates "forces [him] to leave" (314) and thus "takes command of the little community." He "must induce Cephalus to leave the scene, because Cephalus is beyond reason, and it would be impious to dispute him." The removal of the authority frees Socrates and company for a "critical examination of the ancestral code."
I have to say first of all that nothing in this description accords with the direct evidence of the text. Cephalus does not identify very closely with anything ancestral. He regards his own ancestors with marked disapproval, and has only recently come around to a respectful regard for stories about the afterlife (having laughed at them in his youth). He does not have a place of authority in the household, which is identified in the text as "Polemarchus's house," not "Cephalus's house," because Polemarchus has already taken over the estate. Socrates does not scruple to dispute Cephalus. On the contrary he raises a direct argument against him. Also, by Sorates's own testimony, he is eager to hear more from Cephalus, not eager to be done with him. We have no reason to think that Cephalus departs in reaction to the conversation, since we are given the very plausible explanation that he has to attend to the sacrifices.
I suppose Bloom could chalk all of this evidence up to a mixture of Socratic and Platonic irony, but this all-powerful magical hermeneutical device of appeal to irony would not excuse him from indicating some positive evidence explaining how he has come to get the inside story that the rest of us can't see. But all he can point to is the association of Cephalus with sacrifices, which we do not need to connect with "ancestral piety," since Cephalus has explained that he is more or less just hedging his bets.
More next time on Stanley Rosen, Leo Strauss, Julia Annas, and Devin Stauffer, before I finally move on to the refutations of Polemarchus.